Answer:
Looking for light
Explanation:
Since plants require sunlight in order to produce light, they need to be exposed to it. Now, since there are other plants attempting to do the same they have to grow higher so they don't get put in the others shadow and possibly die due to lack of sunlight.
The fly species Drosophila santomea is found only on a single small island. Thus, this fly is considered to be "Endemic".
I would say presence of inorganic molecules I THINK not sure.